Over 30,000 end-stage renal disease (ESRD) patients are waiting for cadaveric kidney transplantation. This number is expected to double in five years. In the last decease, the number of kidneys from cadaver donors has remained stagnant at 7,500-8,000/year. Although living renal donation is accepted as a low risk procedure with superior allograft survival, only 25% of transplants performed in European Americans and 10% of transplants in African americans are from living donors. factors governing the supply of living renal donors are not well understood. Despite well-established criteria for donor nephrectomy, variable which influence the outcomes of donor evaluation/selection process have not been rigorously studied. The goals of this project are to: (I) identify and describe the obstacles to the supply of living renal donors; (ii) identify the medical diagnoses, laboratory findings and non-medical factors which impact the outcomes of donor selection/evaluation process and ; (iii) analyze the relationships between the predictors of living renal donation and the characteristics of various ESRD populations. A quasi-experimental design with statistical adjustment for baseline characteristics will be applied. the sampling frame is a consecutive sample of three cohorts (transplant candidates, evaluable and unevaluable potential donors) from two transplants centers (University of Michigan and Henry Ford Hospitals). Clinical and laboratory investigations and multi-stage, longitudinal, interviewer-administered, validated survey instruments will be prospectively applied to 840 transplant candidates and 420 potential donors. Descriptive and multi variate techniques will be used to analyze the relationships between the probability of being a donor and 3 classes of explanatory variables: (1) demographics, cultural beliefs and socioeconomic characteristics; (2) medical diagnoses and serologies; and (3) ABO blood groups and positive crossmatch. The relationship between familial size and the pool of potential living donors will also be analyzed. A cohort of donors will be prospectively followed for overall health and renal outcomes. The proposed project will yield additional information needed to build effective public health campaigns to improve living donor awareness, increase the donor pool and bring the benefit of kidney transplantation to more ESRD patients, particularly the minority patients, among whom access to transplantation is an even greater problem. The prospective donor database will demonstrate the feasibility of a multi- center living renal donor registry which is essential to future research in living renal donation.